I have a docx file that I get an error when trying to download(document cannot be found).... .doc is fine .txt is also fine. I am sure this is just an iis setting, the permissions on the server are all the same for all files.

4 Answers
4

To allow .docx files to be downloaded, follow the steps from the KB article linked above:

Open the IIS Microsoft Management Console (MMC), right-click the local computer name, and then click Properties.

Click MIME Types.

Click New.

In the Extension box, type the file name extension that you want (in this case, .docx).

In the MIME Type box, type application/vnd.openxmlformats-officedocument.wordprocessingml.document (thanks to @web developer for pointing out this MIME type, which supercedes the 'application/msword' from my original answer).

Apply the new settings. Note that you must restart the World Wide Web Publishing Service or wait for the worker process to recycle for the changes to take effect. In this example, IIS now serves files with the .docx extension.

Note that the KB article uses the generic application/octet-stream MIME type: although that generally should work, if a more specific MIME type exists, such as application/msword, it's always best to use that.

Other than that, and just because you did not specify where the error shows up: When you forbid caching in a header, similar behavior may occur on the client. But that is a general issue, and not bound to .docx.